Field of the Invention
The present invention relates to an ink jet head capping device in an ink jet printing apparatus.
In a conventional ink jet head capping device, as shown in FIG. 5, a cleaning belt 15 carrying scraping strips 25 is arranged in parallel with, and alongside, a cap 14 and receives a driving force from a driving belt 19 to undergo rotation. An arm 16 supports cleaning belt 15 and cap 14, and is carried by a support shaft 20 to undergo pivotal movement therearound to switch between a capped state and a released state with respect to an ink jet head (not shown) disposed above cap 14. Further, in color ink jet printing, four heads are provided for four printing inks, for example of yellow, magenta, cyan and black, so that three more caps must be added adjacent to the cap 14 of FIG. 5 in parallel to the support shaft 20. Therefore, the apparatus must be enlarged in the axial direction of support shaft 20, i.e. in the printing width direction. In such case, a single cleaning belt is commonly utilized to sequentially effect cleaning of the four color ink nozzles, rather than providing three additional cleaning belts, so as to save space.
In the above noted construction, additional space is needed in the axial direction of support shaft 20, and an ink jet capping device must be disposed within the ink jet head printing apparatus but outside the printing region, thereby causing the drawback that the overall dimension of the printing apparatus is enlarged, especially in the widthwise direction of a printing paper sheet. Such drawback is quite disadvantageous in view of the recent demand for miniaturization of the printing apparatus.
Further, in case such structure is adapted for color ink jet printing apparatus, a single cleaning belt 15 may be commonly utilized to effect sequential cleaning of respective color inks, since four cleaning belts could not be provided for the four color inks in view of the above noted space limitations. Therefore, previously, cleaned ink of one color may be deposited on an adjacent head for another color to be cleaned, to thereby cause mixing of the inks, resulting in serious degradation of image quality.